The present invention relates to a collimator, an X-ray irradiator, and an X-ray apparatus. Particularly, the present invention is concerned with a collimator for defining an X-ray irradiation range, as well as an X-ray irradiator and an X-ray apparatus both provided with the collimator.
In an X-ray irradiator there is used a collimator for defining an X-ray irradiation range. The collimator has an aperture which permits the passage of X-ray therethrough. The other portion than the aperture of the collimator does not permit the passage of X-ray. The degree of opening of the aperture is changeable, whereby the X-ray irradiation range can be adjusted.
The collimator with such an adjustable aperture has movable plate members, i.e., blades, possessing X-ray absorbability. There are used a pair of blades having respective end faces opposed to each other. The pair of blades are movable in directions opposite to each other in a plane parallel to their surfaces. For widening the aperture, the pair of blades are moved in directions away from each other, while for narrowing the aperture, the pair of blades are moved toward each other.
For reducing the collimator size without sacrificing the adjustable range of the aperture, there has been proposed an X-ray irradiator wherein blades are constructed of a flexible material and are wound onto drums to widen the aperture, while they are delivered from the drums to narrow the aperture (see, for example, Patent Document 1).
[Patent Document] Japanese Published Unexamined Patent Application No. 2002-355242 (pages 2–3, FIGS. 1–2)
In the above conventional collimator there is the problem that a special material which is flexible and superior in X-ray absorbability must be used as the blade material.